It is certainly a possibility to completely rely on FFS for the syncing process. I think that @tambo is exploring this route. However, I still use Icedrive’s syncpairs, and use FFS to “check and correct”. So every now and then I have FFS compare my local drive with my mounted drive (which in fact represents the cloud), like this:
The settings for the comparison should be “date and size”:
If FFS finds any discrepancies, I hit the synchronize button. Make sure that the settings for synchronization are set to “mirror”, so that FFS only syncs in one way, and leaves your local drive undisturbed:
Good question. I think it does, because I assume that the mounted drive reflects exactly what lives in the cloud. It doesn’t contain files itself, but is more like a portal to the cloud. (Can anyone confirm this view?) So if FFS finds no problems, the local drive and the cloud should be exactly the same. Having said that, there is still the problem of file corruption (see the comment by @Abe above), which FFS probably won’t detect.